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VIN 6




DTC P0483 or P0493 (LMM)

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provides an overview of each diagnostic category.

DTC Descriptor
DTC P0483
- Cooling Fan System Performance

Diagnostic Fault Information





Circuit/System Description

The cooling fan relay sends a pulse width modulation (PWM) signal of 12-14 volts to the cooling fan clutch through the cooling fan clutch supply voltage circuit. The engine control module (ECM) uses this PWM signal in order to control the speed of the cooling fan clutch. The signal controls the position of the oil control valve inside the cooling fan clutch.

Conditions for Running the DTC

* The engine coolant temperature is warmer than 70°C (158°F).
* The engine RPM is greater than 1,200 RPM.
* The fan duty cycle is greater than 36 percent.
* The engine speed variation is less than 250 RPM.

Conditions for Setting the DTC

The difference between the commanded and the actual cooling fan speed is greater than 500 RPM for greater than 120 seconds.

Action Taken When the DTC Sets

DTC P0483 is a Type C DTC.

Conditions for Clearing the DTC

DTC P0483 is a Type C DTC.

Reference Information
Schematic Reference

Engine Cooling Schematics (Diagrams)
Connector End View Reference

Component Connector End Views (Connector End Views By Name)
Description and Operation

Cooling Fan Description and Operation (with RPO LMM) (Cooling Fan (with VIN 6)) Cooling Fan Description and Operation (W/LGH) (Cooling Fan Description and Operation (with VIN L))
Electrical Information Reference

* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions (Powertrain Diagnostic Trouble Code (DTC) Type Definitions)
Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information

Circuit/System Verification

1. Ignition OFF, inspect the cooling fan and the drive belt for the following conditions:

* A cracked drive belt
* A loose or a worn drive belt
* A misrouted drive belt
* Oil leaks at the cooling fan clutch
* A free-spinning cooling fan
* A seized cooling fan clutch
* A broken cooling fan

2. Idle the engine.
3. Command the cooling fan clutch to 10 percent with a scan tool.
4. Operate the engine at 1,500 RPM for 2 minutes. The fan should be quiet to indicate the clutch is disengaged.
5. Command the cooling fan clutch to 80 percent, with a scan tool.
6. Operate the engine at 1,500 RPM for 2 minutes. Observe the difference between the scan tool Fan Speed and Desired Fan Speed parameters. The difference should remain less than 1,000 RPM throughout the speed transition.
7. Observe the DTC information with a scan tool. Verify DTC P0483 is not set.
8. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Circuit/System Testing

1. Ignition OFF, disconnect the cooling fan or fan clutch relay.
2. Test for less than 3 ohm between the fan relay ground circuit terminal K9, or relay terminal 6 and ground.

• If greater than the specified range, test the ground circuit for an open/high resistance.

3. Operate the engine at 1,500 RPM for 2 minutes. The fan should be quiet to indicate the clutch is disengaged.

• If not disengaged, test the cooling fan clutch supply voltage circuit for a short to voltage. If the circuit tests normal, replace the fan clutch.

4. Ignition OFF, connect a 10 A fused jumper wire between the cooling fan clutch supply voltage circuit terminal K11, or relay terminal 4 and B+.
5. Operate the engine at 1,500 RPM for 2 minutes. The fan should be loud to indicate the clutch is engaged.

• If not engaged, test the cooling fan clutch supply voltage circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the fan clutch.

6. Ignition OFF, connect a 10 A fused jumper wire between the relay voltage supply circuit terminal J12, relay terminal 2, and the cooling fan clutch supply voltage circuit terminal K11, relay terminal 4.
7. Operate the engine at 1,500 RPM for 2 minutes. The fan should be loud to indicate the clutch is engaged.

• If not engaged, test the relay voltage supply circuit for a short to ground or an open/high resistance. If the circuit tests normal and the fuse is open, test all the components connected to the fuse and replace as necessary.

8. Ignition OFF, connect a test lamp between the cooling fan clutch relay control circuit terminal L12, relay terminal 5 and B+. The test lamp should not illuminate.

• If the test lamp illuminates, test the control circuit for a short to ground.

9. Engine operating at 1,500 RPM, command the cooling fan clutch to 80 percent for 2 minutes, with a scan tool. The test lamp should illuminate or flash, indicating that the ECM can control the relay.

• If the lamp does not illuminate or flash, test the cooling fan clutch control circuit for an open/high resistance, or for a short to voltage. If the circuit tests normal, replace the ECM.

10. Perform the relay component test. The relay should test normal.

• If the relay does not test normal, replace the relay.

11. Ignition OFF, disconnect the fan clutch harness at the cooling fan shroud.
12. Test for less than 3 ohm between ground and the low reference circuit terminal C.

• If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.

13. Ignition ON, test for 4.8-5.2 V between the 5-volt reference circuit terminal E and the low reference circuit terminal C.

• If less than the specified range, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.
• If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the ECM.

14. Connect fused jumper wires between the harness and sensor pigtail connectors for the circuit terminals listed below:

* 5-volt reference circuit terminal E
* Low reference circuit terminal C

15. Ignition ON, measure voltage between the signal circuit terminal D at the sensor pigtail connector and the 5-volt reference circuit jumper wire terminal, while rotating the cooling fan by hand. The voltage should toggle between approximately 5 V and 0 V.

• If the voltage does not toggle correctly, test the circuits/connections in the pigtail harness. If the circuits test normal, replace the fan clutch.

16. Leave the fused jumper wire from the previous step connected to the 5-volt reference circuit terminal E at the harness side of the connector. Momentarily touch opposite end of the jumper wire to the signal circuit terminal D of the harness connector, while observing the scan tool Fan Speed parameter. The parameter should display a speed above 0 RPM when the signal circuit is repeatedly toggled to 5 V.

• If the Fan Speed parameter does not display a speed greater than 0 RPM, test the signal circuit for a short to ground, a short to voltage, or an open/high resistance. If the circuit tests normal, replace the ECM.

17. If all the relay and the speed sensor circuits/connections, test normal, replace the cooling fan clutch.

Component Testing

Relay Test
1. Connect the relay ground terminal to ground and the voltage supply terminal to appropriately fused power to energize the relay.
2. Test for less than 1 V between the load voltage supply terminal and ground.
3. Connect the relay control circuit terminal to ground.
4. Test for B+ between the load voltage supply terminal and ground.

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Fan Clutch Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for replacement, setup, and programming

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